Very wary tigers!
August 14, 2012 7 Comments
In late July I found a new tiger beetle site in southeastern Missouri—a small sandbar along the Mississippi River near Cape Rock Park on the north side of Cape Girardeau. I originally went to the park to look for Cylindera cursitans (Antlike Tiger Beetle), two specimens of which my friend and colleague Kent Fothergill had found in the collection of a local lepidopterist (MacRae et al. 2012). I thoroughly searched the areas that looked suitable for that species, but to no avail. I did, however, spot the sandbar down by the river and knew immediately that it had good potential for several species typically found in such habitats. Even before hiking down the rocky embankment I figured I would see Cicindela repanda (Bronze Tiger Beetle)—dreadfully common along almost every waterway in the state. What I was really hoping to see, however, were some of the more specialty species found only in wet sand habitats along the big rivers of the state—the Missouri and mighty Mississippi.
Predictably, C. repanda was present and abundant, but it wasn’t long before I spotted some individuals that looked just a little bit different—stockier and with the white markings a little more distinct. A closer look confirmed that these were C. hirticollis shelfordi (Shelford’s Hairy-necked Tiger Beetle). It had been a while since I’d seen this species, and it occurred to me that the only photos I had of it were taken with my point-and-shoot prior to getting my dSLR setup. I then realized also that I didn’t even have good photographs of C. repanda—I’ve been so focused on photographing rare and unusual species over the past few years that I’ve completely neglected photographing our state’s most common resident.
Over the years, I’ve learned a number of tricks that have allowed me to be fairly successful at approaching tiger beetles closely for photography—working a population to find that one slightly more cooperative individual, and then working that one individual until it becomes accustomed to my presence, perhaps allowing it to “hide” under debris before carefully removing its cover or even “trapping” it in a relatively confined area until it settles down enough to allow photographs. But nothing, not a single thing I tried, worked on this day. As it was through much of July and early August, temperatures were extreme—already well into the 90s despite my mid-morning arrival. Combined with the wide open spaces and a blazing hot sun, the beetles were already extremely active and very wary. The sandbar itself offered little help in corralling the beetles—stark, barren, devoid of any debris or other potential shelters that could be used to my advantage. Stubbornness prevented me from accepting this fact, so I spent the good part of two hours slowly stalking each beetle that looked like it might cooperate, only to have it fly before I could even get down on all fours or, once I did, run incessantly to the point that it was almost impossible to settle it in the frame—much less compose a decent closeup shot. Eventually I decided that the only way I was going to get a beetle standing still in the frame with any degree of closeness was to approach it from the front and try to catch it in one of its intermittent “stilting/sun facing” poses—a thermoregulatory behavior that tiger beetles employ when the sun heats the soil surface to temperatures that would be lethal for many other insects. The first shot in this post is the best of that type that I could manage (although I like its composition very much—I just wish I’d been able to get some closer shots as well).
As suggested above, C. repanda and C. hirticollis are quite similar in appearance, and at least in Missouri the latter is always found in association with the former, though only in wet sand habitats along the big rivers and not nearly in the same numbers as C. repanda. Until one develops a feeling based on “gestalt” it can be difficult to pick out individuals of C. hirticollis amongst the commoner C. repanda. I’ve already mentioned their slightly huskier build and somewhat bolder white markings, and C. hirticollis also tends to exhibit a slightly more coppery cast to the body. The surest character to use, however, is the “G”-shaped humeral lunule, which is the white marking on the “shoulders” of the elytra just behind the pronotum. The posterior portion of this marking is nearly transverse and usually angles sharply anteriorly on its inner edge. By contrast, in C. repanda this marking is always “C”-shaped and never curls forward on its inner edge. These characters can be compared in the lateral profile photos of the two species above and below (though not as closely as I would like).
I should mention that there was one other big river specialty species present on the sandbar—Ellipsoptera cuprascens (Coppery Tiger Beetle). I saw only a few individuals of this species and couldn’t get close enough to one of them to even fire off a single shot. For this species, however, I still had one more trick up my sleeve that allowed me to photograph it to my heart’s content (no, not capturing one and confining it in a terrarium!)…
MacRae, T. C., C. R. Brown and K. Fothergill. 2011. Distribution, seasonal occurrence and conservation status of Cylindera (s. str.) cursitans (LeConte) (Coleoptera: Cicindelidae) in Missouri. CICINDELA 43(3):59–74.
Copyright © Ted C. MacRae 2012